Air droppable apparatus



Dec. 3, 1968 c. J. RUSSNAK AIR DROPPABLE APPARATUS Filed June 22, 1967cum/c5 J RUSS/MK United States Patent 3,414,218 AIR DROPPABLE APPARATUSClarence J. Russnak, Scottsdale, Ariz., assignor to M0- torola, Inc,Franklin Park, IlL, a corporation of Illinois Filed June 22, 1967, Ser.No. 648,080 7 Claims. (Cl. 244138) ABSTRACT OF THE DISCLOSURE Acylindrical housing with an X-shaped spear or spike with a conicalsection adjacent one end of the housing and a set of stabilizing fins atthe opposite or upper end which have a tapered upper edge foraccommodating rotochute blades when the blades are just beginning torotate. An antenna extends coaxially upwardlly past the rotochute.Provisions are made for attaching a parachute in lieu of using arotochute.

Background of the invention The present invention relates generally toair droppable apparatus and, more particularly, to such apparatusadapted to remain in an upright position after landing.

There have been several forms of air d-roppable apparatus most of whichare suitable primarily for high altitude air drops or when used at lowaltitudes for low air speeds. Such prior devices include devices with anelongated round spike or spear on one end for penetrating the ground.Such spikes were good for high altitude drops but do not penetratesufiicient to keep the apparatus in an upright position when dropped atlow altitudes. Further, when dropped from high speed aircraft suchapparatus have a tendency to roll over and assume a horizontal position.

When air droppable apparatus is used to establish a radio communicationlink or a radio beacon, it is quite important that the antenna in theapparatus be in an upright position. Air craft height and speed arerelative for a successful drop; the greater the speed, the higher theaircraft must be for a successful drop. Also, such round points do notpenetrate paved surfaces sufficiently for successful implantation. Suchdevices have used rotochutes or parachutes for use as air brake for rateof descent control. I

When air drop velocity is high there is a substantial impact uponhitting the ground. When air dropped apparatus is carrying fragileelectronic apparatus, for example, means have been provided forprotecting the apparatus from shock. Such additional means, includinghydraulic shock absorbers, and weight to the apparatus and, therefore,reduce the cargo carrying capacity.

Generally, stabilizing fins have been added to the apparatus to keep itfrom unduly spinning as it descends. When using such stabilizing finswith a rotochute, for example, such fins can interfere with theoperation of the rotochute or the fins can be placed midway of theapparatus housing which adds certain undesirable instabilities to thedescent.

Summary of the invention It is an object of the present invention toprovide a lightweight air droppable apparatus which can land in anupstanding manner from low altitude high speed release.

3,414,218 Patented Dec. 3, 1968 ice the features of having a cylindricalhousing with an X or star-shaped ribbed spike or spear on one endportion and a descent air velocity limiting means on the other or upperend portion, such as a rotochute or parachute. An antenna may extendcoaxially through the rotochute. The starshaped spear has two lportions;the first or lower portion has a very small taper in the outwardlyprojecting ribs, for example, the lower one-third length of the spear,while the latter two-thirds or upper portion has a much greater taper inthe ribs. Also, immediately adjacent to the housing and the portion withthe greater ta pered ribs there is provided a conical projection forlimiting the penetration when it lands in sand. The spear is in threadedengagement with the housing for facilitating removal and as sembly.

The upper portion of the housing includes a rotochute with stabilizingfins extending between the rotochute blades when in an unactuatedposition. The upper edges of the fins are tapered. As the apparatusbegins to drop, the rotochute blades move outwardly without rotation.Before the rotochute blades begin to rotate, the blades have reached aposition above the tapered upper edge of the stabilizing fins and,therefore, clear the fins upon the onset of rotation. This arrangementpermits the fins to be at a maximum rearward or upper position on thehousing for maximum stability of descent. The device center of gravityis preferably below the axial center of the housing and the load ispreferably balanced about the axial center line of the housing.

The drawing FIG. 1 is a side elevational view of one apparatusincorporating teachings of the present invention.

FIG. 2 is a partial exploded view of the front end portion of the FIG. 1apparatus showing how the X-shaped point attaches to the cylindricalhousing.

FIG. 3 is a front elevational view of the FIG. 1 apparatus showing theoutwardly projecting ribs of the front end spear and the stabilizingfins.

Description of the illustrative embodiment Like numbers and charactersindicate like parts and structural features in the various views. Theillustrative apparatus includes cylindrical housing 10 for containingelectronic apparatus 16 or other air cargo. Housing 10 has lower endportion 11 and upper end portion 12 indicating the upper and lower endsduring descent. Air drop velocity limiting means, such as a rotochute13, is attached to upper end portion 12. It is understood that aparachute may be substituted for rotochute 13 as by threading the cordsof a parachute through the apertures in collar 14. Collar 14 isthreadingly engaged to the upper end portion 12 and may be used totightly fit against cargo 16 inside housing 10. In this embodiment cargo16 is a radio device housing upwardly projecting antenna 17. Novelribbed spear 15 is threadingly engaged to lower end portion 11 and isdesigned to penetrate hard pavement, such as asphalt, as well asproviding good resistance to penetration of soft sand such that theapparatus can remain in an upstanding position when landing on eitherextreme surface types with minimum landing shock. When housing 10 isupright, antenna 17 extending axially outwardly from end portion 12 isin an upright preferred operating position. A set of novel stabilizingfins 20, 21, 22, and 23 are fixedly attached to the upper end portion 12as shown. Housing 10 has central axis 18 around which all weight issymmetrically distributed. The center of gravity 19 is preferably closerto end portion 11 than portion 12 to make the descent more stable andensure that spear 15 is always pointed downward after release from anaircraft (not shown).

Spear 15 is especially designed for high speed low altitude air drops,as will become apparent. Spear 15 includes a plurality of outwa ndlyprojecting ribs 30, 31, 32, and 33 symmetrically disposed about axis 18.The lower one-sixth portion 34 of spear 15 has a very small taper suchas A1" in 3" in the ribs from the extreme point for providing ease ofpenetration into hard surfaces, such as asphalt. This lower portion,which may be up about /3 the length of the spear, ensures that airdropped apparatus can be in an upstanding position when landing on ahard surface. The ribs of upper five-sixths portion 35 of spear 15 havea greater taper such as twice the lower portion and act as a cushionwhen the apparatus is penetrating into the ground. The greater taperalso adds to the stability of the apparatus after it has landed.Further, spear 15 is provided with depending cone 36 symmetricallyformed about axis 18 and extending, for example, along the upperone-third portion or less, as best seen in FIG. 1. Cone 36 is adapted toact as a brake when the air dropped apparatus lands in a soft surfacesuch as sand or swampy ground. It also serves as an additional cushionas spear 15 is penetrating the ground.

The terms high and low altitudes, as used herein, refer to the relativespeed at release with respect to actual altitude. As an example, a highspeed low altitude drop using an air droppable apparatus such asdescribed was repeatedly successfully dropped at an altitude of 350 feetat an air speed of 150 knots. A successful drop means the FIG. 1illustrated apparatus remained in an upstanding position with spear 15penetrating ground surface. At higher altitudes, aircraft speeds can beproportionately increased. The above cited figures represent a highspeed low altitude drop. Such air drops were successful even when theportion 12 was pointed downward at release.

Referring now more particularly to FIG. 2, there is illustrated in anexploded view the connection between spear 15, housing 10, andelectronic apparatus 16. Spear 15 has axially extending, externallythreaded projection 40 for receiving the inner coarse threads 41 ofcollar 42 and being in threaded engagement with housing 10. Collar 42has a set of fine external threads 43 to engage fine internal thread 44of the housing 10. It has been found that the use of the collar 42 asdescribed provides a facile connection between spear 15 and housing andpermits air cargo 16 to be securely directed against spear such that thecushioning effect of spear 15 can be utilized.

The upper portion of the apparatus will be now described in more detail.The fins 20, 21, 22, and 23 are fixedly secured to the housing 10 as bya pair of annular straps 49, as shown. The fins are preferably as farupward along portion 12 as possible to ensure stable descent. To thisend, the fins are all tapered at the upper edges as at 51 to accommodatethe blades of rotochute assembly 13. The taper 51 is designed such thatwhen the rotochute 13 blades have opened outwardly from the air passingby and are just beginning to rotate, the blades clear the fin inwardlyupper tapered edges 51. Rotochute 13 is rotatably secured to the base ofantenna 17 by clamp 50.

The entire apparatus can easily be assembled by first affixing spear 15to housing 10 and then inserting air cargo 16 with collar 42 attachedand threadingly engaging it into projection 40. Then collar 14 may bethreadingly engaged in the upper end portion 12 for holding cargo 16securely inside housing 10. It should be noted that antenna 17 extendscoaxially through collar 14. Then annular straps 49 are secured tohousing 10 in a clamping manner. Then rotochute 13 is securely attachedto the base of antenna 17 by clamp 50. When a parachute is used with theapparatus, rotochute 13 is not included in the assembly and a parachuteis affixed to collar 14 through the illustrated apertures 14A.

I claim:

1. Air droppable apparatus, including in combination,

a cylindrical housing with upper and lower end portions and having anaxis along its length central of the cylinder,

an axially extending spear on said lower end portion symmetrical aboutsaid axis and having a plurality of radially outwardly extending ribssymmetrically disposed about said axis and tapered from a maximum radialdimension immediately adjacent said lower end portion to a minimumradial dimension at an extreme point disposed axially from said lowerend portion away from said upper end portion, said ribs tapering fromsaid extreme point at a relatively small angle up to about betweenone-sixth and onethird the length of said spear and at a much greaterangle between said lower end portion and said small angle taper of saidspear, said ribs having platelike radial surfaces,

air velocity limiting means on said upper end portion,

a conical projection extending from said lower end portion along saidaxially extending spear filling the space between adjacent radiallyextending ribs and tapering to a point not more than one-third thedistance from said lower end portion toward said extreme point alongsaid axis, and

a plurality radially outwardly extending stabilizing fins symmetricallydisposed about said axis on said upper end portion.

2. The apparatus of claim 1 wherein said air velocity limiting meanscomprises rotochute means secured to said upper end portion withrotatable blades when in an unactuated position lying between saidradially extending fins, each fin having an upper end portion and aradially outward portion and a tapered portion extending from said upperend portion radially outwardly toward said radially outward portion suchas to form an upper edge including a tapered portion forming an acuteangle with said cylinder with the apex of the acute angle pointingtoward said upper end portion.

3. The apparatus of claim 1 wherein said small angle taper is one-eighthinch in three inches and extends for one-sixth the length of said spear.

4. The apparatus of claim 1 wherein said spear has an upwardly extendingprojection with outer threads, a collar threadingly engaging said outerthreads, and

the collar further including internal and external threads with theexternal threads engaging internal threads on said housing.

5. The apparatus of claim 4 wherein said collar internal threads arecoarser than said collar external threads.

6. The apparatus of claim 1 further including a collar threadinglyengaged to the upper end portion of said housing and having aperturesfor receiving a parachute and operative to securely hold air cargowithin said housing.

7. The apparatus of claim 1 wherein there are four radially outwardlyextending stabilizing fins and four outwardly extending ribs with thefins and the ribs each forming an X symmetrically about said axis.

References Cited UNITED STATES PATENTS 3,288,402 11/1966 Icenbice et a1.244-138 417,433 12/1889 Lorenz 43-6 1,250,178 12/1917 Hover 102-3 X2,417,980 3/1947 Goss 102-2 2,440,291 4/1948 Pitcairn 244-138 2,978,2114/1961 Wannlund et al. 244-138 3,013,493 12/1961 Fletcher 102-3563,016,217 1/1962 Polleys et al. 244-138 3,098,445 7/1963 Jackson 102-49FOREIGN PATENTS 82,073 8/1919 Switzerland.

MILTON BUCHLER, Primary Examiner. RICHARD A. DORNON, Assistant Examiner.

